Promag ignition troubleshooting

Discussion in 'PSI Superchargers Tech Questions' started by overkill69, Aug 5, 2014.

  1. overkill69

    overkill69 Member

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    I've posted a couple times on this troubleshooting and we still don't have a smoking gun.
    Recap
    Sent all the promag stuff to Lahey over the winter. Did not send the 8973.
    On fireup the car had a severe misfire around 6500 rpm on jacks. It idled clean and responded clean at higher rpms.
    I reloaded a new file into the 8973 and the car seemed cured and made 6 of our fastest laps ever.
    The only issue with the box was the rpm based timing curve would not dump timing when commanded.

    At the next race we made a lap with a burned pushrod and broke the blower belt which smacked the points box and coil.
    The data logger memory became corrupted and would not work.
    It took a couple broken belts to figure out the ignition was shutting off and on at various points during the run.
    I changed the points box and bypassed the mag kill solenoid with no improvement.
    Everything on the car has been inspected and the car shuts off slowly without the kill solenoid which seems to verify the capacitor is ok.

    All the mag stuff was load tested today and came back good.

    Our plan for the next race
    new plug wires-not msd-suggestions?
    new point box
    new coil
    new crank trigger and harness to 8973
    delete ground solenoid
    load test cars battery
    new cap rotor and adapter for mag
    have setup in the trailer to wire directly from battery to 8973 if required

    the biggest risk is the 8973. Can MSD do any useful checks? Anybody have a tech contact?
    Everybody I know runs the powergrid so i'll be forced to switch if I can't come up with something solid.

    Thanks
    Mike Bruns

    http://youtu.be/CAJBVGLLUWE
     
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  2. Mike Canter

    Mike Canter Top Dragster
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    Do you have a crossover switch for switching between the crank trigger and the mag. If so I would highly recommend make a run with the switch out of the circuit and have the 8973 hooked directly to the crank trigger or the mag. I have seen this exact problem and it was caused by engine vibration making the contacts in the crossover switch bounce and cause the engine to shut off and turn back on at a real fast rate. Also caused the belt to break and damage pushrods
     
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  3. overkill69

    overkill69 Member

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    44!88

    No switch on the trigger
     
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  4. Sportsman

    Sportsman TA/FC

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    Did you check the plugs & wires with an OHM meter?
     
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  5. planbmotorsports

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    Do you have a tach convertor box? They can cause all kinds of crazy issues. If you have one I would eliminate it completely.
     
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  6. Mike Canter

    Mike Canter Top Dragster
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    Ok, if no crossover switch then have you tried running it off the mag vice the crank trigger. If you are interested I know where there is a brand new never used 8973 in a box for $200.
     
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  7. overkill69

    overkill69 Member

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    Please send a phone number I'll take it.
     
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